For questions about the VLAN Trunking Protocol

VLAN Trunking Protocol (VTP) is a Cisco proprietary protocol that propagates the definition of Virtual Local Area Networks (VLANs) on the whole LAN. To do this, VTP carries VLAN information to all the switches in a VTP domain. VTP advertisements can be sent over 802.1Q, and ISL trunks. VTP is available on most of the Cisco Catalyst Family products. Using VTP, each Catalyst Family Switch advertises the following on its trunk ports:

  • Management domain
  • Configuration revision number
  • Known VLANs and their specific parameters

There are three versions of VTP, namely version 1, version 2, version 3.